High strength electric resistance welded steel pipe and method for producing high strength electric resistance welded steel pipe

• US 10,640,843 B2
• Filed: 02/15/2016
• Issued: 05/05/2020
• Est. Priority Date: 05/20/2015
• Status: Active Grant

• Current Assignee: Nippon Steel Corporation
• Original Assignee: Nippon Steel Corporation
• Inventors: Ishitsuka, Tetsuo, Iwamoto, Shuji, Tsusue, Takashi, Kobayashi, Shunichi, Yoshida, Osamu, Kawano, Hideto
• Primary Examiner(s): La Villa, Michael E.
• Application Number:
  US15/561,337
• Publication Number:
  US 20180105893A1
• Time in Patent Office: Days
• CPC Class Codes: B21B 1/026 Rolling
• CPC Class Codes: B21B 1/22 for rolling plates, strips, bands or sheets of indefinite length B21B1/42 takes precedence
• CPC Class Codes: B21B 2001/028 Slabs
• CPC Class Codes: B21B 2001/225 by hot-rolling
• CPC Class Codes: B23K 11/0873 of the longitudinal seam of tubes
• CPC Class Codes: B23K 11/16 taking account of the properties of the material to be welded
• CPC Class Codes: B23K 2101/06 Tubes
• CPC Class Codes: B23K 2103/04 Steel or steel alloys
• CPC Class Codes: B32B 1/08 Tubular products
• CPC Class Codes: B32B 15/00 Layered products comprising a layer of metal
• CPC Class Codes: C21D 2211/005 Ferrite
• CPC Class Codes: C21D 6/001 containing Ni C21D6/004 takes precedence
• CPC Class Codes: C21D 6/004 containing Cr and Ni
• CPC Class Codes: C21D 6/005 containing Mn
• CPC Class Codes: C21D 6/008 containing Si
• CPC Class Codes: C21D 8/02 during manufacturing of plates or strips C21D8/12 takes precedence
• CPC Class Codes: C21D 8/0205 of ferrous alloys
• CPC Class Codes: C21D 8/0226 Hot rolling
• CPC Class Codes: C21D 8/0263 following hot rolling
• CPC Class Codes: C21D 8/105 of ferrous alloys
• CPC Class Codes: C21D 9/08 : for tubular bodies or pipes
• CPC Class Codes: C21D 9/085 : Cooling or quenching
• CPC Class Codes: C21D 9/46 : for sheet metals
• CPC Class Codes: C21D 9/50 : for welded joints
• CPC Class Codes: C21D 9/505 : Cooling thereof
• CPC Class Codes: C22C 38/00 : Ferrous alloys, e.g. steel alloys cast-iron alloys C22C37/00
• CPC Class Codes: C22C 38/001 : containing N
• CPC Class Codes: C22C 38/002 : containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
• CPC Class Codes: C22C 38/005 : containing rare earths, i.e. Sc, Y, Lanthanides
• CPC Class Codes: C22C 38/02 : containing silicon
• CPC Class Codes: C22C 38/04 : containing manganese
• CPC Class Codes: C22C 38/06 : containing aluminium
• CPC Class Codes: C22C 38/08 : containing nickel C22C38/105 takes precedence
• CPC Class Codes: C22C 38/12 : containing tungsten, tantalum, molybdenum, vanadium, or niobium
• CPC Class Codes: C22C 38/14 : containing titanium or zirconium
• CPC Class Codes: C22C 38/16 : containing copper
• CPC Class Codes: C22C 38/18 : containing chromium
• CPC Class Codes: C22C 38/20 : with copper
• CPC Class Codes: C22C 38/22 : with molybdenum or tungsten
• CPC Class Codes: C22C 38/26 : with niobium or tantalum
• CPC Class Codes: C22C 38/28 : with titanium or zirconium
• CPC Class Codes: C22C 38/40 : with nickel
• CPC Class Codes: C22C 38/42 : with copper
• CPC Class Codes: C22C 38/44 : with molybdenum or tungsten
• CPC Class Codes: C22C 38/46 : with vanadium
• CPC Class Codes: C22C 38/48 : with niobium or tantalum
• CPC Class Codes: C22C 38/50 : with titanium or zirconium
• CPC Class Codes: C22C 38/58 : with more than 1.5% by weight of manganese
• CPC Class Codes: F16L 9/00 : Rigid pipes
• CPC Class Codes: F16L 9/16 : wound from sheets or strips, with or without reinforcement
• CPC Class Codes: F16L 9/165 : of metal
• CPC Class Codes: F16L 9/17 : obtained by bending a sheet longitudinally and connecting the edges
• CPC Class Codes: Y10T 428/12799 : Next to Fe-base component [e.g., galvanized]
• CPC Class Codes: Y10T 428/12951 : Fe-base component
• CPC Class Codes: Y10T 428/12972 : Containing 0.01-1.7% carbon [i.e., steel]
• CPC Class Codes: Y10T 428/13 : Hollow or container type article [e.g., tube, vase, etc.]
• CPC Class Codes: Y10T 428/26 : Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension

Abstract

Electric resistance welded steel pipe securing the high strength and high toughness demanded from oil well pipe in recent years. The metal structure in a region having a width of 0.5 mm in both the thickness directions from a reference point, when using a point defined as a point ¼ of the thickness in the thickness direction from the surface in the base material part of the steel as the reference point, consists of polygonal ferrite: 10 area % or less and a balance: bainitic ferrite. The thickness is 15 mm or more.

Claims

1. High strength electric resistance welded steel pipe characterized by having a chemical composition consisting of, by mass %,

C:

0.040 to 0.070%,

Si;

0.10 to 0.50%,

Mn;

1.60 to 2.00%,

Nb;

0.020 to 0.080%,

V;

0.060% or less,

Ti;

0.010 to 0.025%,

Mo;

0.20 to 0.40%,

Ni;

0.10 to 0.50%,

Al;

0.050% or less,

3 Mo %+Ni %;

more than 1.00%, and

a balance of Fe and unavoidable impurities,

optionally P;

0.030% or less, S;

0.004% or less, N;

0.006% or less, O;

0.004% or less, Cu;

0.10 to 0.50%, Cr;

0.05to 0.50%, Ca;

0.0005 to 0.0040% and REM;

0.0005 to 0.0050%, and wherein

when using a point defined as a point ¼

of the thickness in the thickness direction from the surface in the base material part of the steel pipe as a reference point, the metal structure in a region having a width of 0.5 mm in both the thickness directions from the reference point as a center consists of polygonal ferrite;

10 area % or less and a balance of bainitic ferrite, and

a thickness is 15.0 to 19.8 mm, and wherein the mechanical properties of the metal structure are such that the tensile strength in the axial direction exceeds 725 MPa, the yield strength in the axial direction is from 655 to 758 MPa, and the Charpy absorbed energy in the circumferential direction at 0°

C. is 22 J or more.

2. The high strength electric resistance welded steel pipe according to claim 1, wherein the polygonal ferrite has an average particle diameter of 20 μ

m or less.

3. The high strength electric resistance welded steel pipe according to claim 1, wherein (3Mo %+Ni %+Cu %) is more than 1.20%.

4. The high strength electric resistance welded steel pipe according claim 3, wherein the polygonal ferrite has an average particle diameter of 20 μ

m or less.

5. A method of producing the high strength electric resistance welded steel pipe according to claim 1, comprising:

hot rolling at 790°

C. or more a hot-rolled steel plate having a chemical composition consisting of, by mass %,

C;

0.040 to 0.070%,

Si;

0.10 to 0.50%,

Mn;

1.60 to 2.00%,

Nb;

0.020 to 0.080%,

V;

0.060% or less,

Ti;

0.010 to 0.025%,

Mo;

0.20 to 0.40%,

Ni;

0.10 to 0.50%,

Al;

0.050% or less,

3 Mo %+Ni %;

more than 1.00%, and

a balance of Fe and unavoidable impurities,

optionally P;

0.030% or less, S;

0.004% or less, N;

0.006% or less, O;

0.004% or less, Cu;

0.10 to 0.50%, Cr;

0.05 to 0.50%, Ca;

0.0005 to 0.0040% and REM;

0.0005 to 0.0050%

cooling the steel plate at an average cooling rate of 8 to 15°

C./sec,

coiling the steel plate at 500 to 630°

C.,

cooling the steel plate at a cooling rate exceeding 5°

C./sec at the beginning of transformation,

forming the steel plate into a tube,

welding end portions of the steel plate by electric resistance welding,

heating the outer surface of the weld zone to 950 to 1050°

C., and cooling the inner surface of the weld zone at a cooling rate of 8°

C./sec or more to a cooling stop temperature of the outer surface of 600 to 450°

C. to obtain the high strength electric resistance welded steel pipe.

6. The method for producing the high strength electric resistance welded steel pipe according to claim 5, wherein the temperature at the start of the transformation is less than 665°

C.

7. The method for producing the high strength electric resistance welded steel pipe according to claim 5, wherein the hot-rolled steel plate is hot-rolled steel plate obtained by heating a slab and hot rolling it with a cumulative rolling reduction rate at 950°

C. or less of 50% or more.